Concrete pump



CCNCRETE PUMP 5 Sheets-Sheet l Filed March 8, 1965 Wwf/uff@ June 27, 1967 R. l.. KLOSTERMAN CONCRETE PUMP 5 Sheets-Sheet Filed March 8, 1965 June 27, 1967 R. L.. KLOSTERMAN CONCRETE PUMP 5 Sheets-Sheet Filed March E, 1965 .Rn @mui CONCRETE PUMP 5 Sheets-Sheet 4 R. l.. KLOSTERMAN June 27, 1967 Filed March 8, 1965 SP] num T" I` if June 27, 1967 R. l.. KLOSTERMAN 3,327,641

CONCRETE PUMP Filed March d, 1965 5 sheets-sheet 5 2a/4r Wwf f4@ E@ 404 C2/f 274/ WMI/f 3?4 1 Y l *E 44a/*af l 30 @y Y I v 7 455 435 l l 4/0 445 A g 4/4 W5 i459 V45 60T l E26. Z 572 /Wyf//Z United States Patent O 3,327,641 CONCRETE PUMP Richard L. Klosterman, Reseda, Calif., assignor to Air Placement Equipment Co., Inc., Grand View, Mo., a corporation of Massachusetts Filed Mar. 8, 1965, Ser. No. 437,760 8 Claims. (Cl. 193-176) This invention relates to a novel and improved concrete pump of the piston type adapted for the pumping of concrete and other similar plastic mixtures which embody relatively large, heavy aggregates. The concrete pump of the invention involves certain more particular improvements which will be referred to presently. In a preferred form of the invention, the concrete pump is trailer mounted, adapting it to be towed to various sites for service. Preferably it is a complete integrated installation on the trailer which is ready for practically immediate service when transported to the site. The pump is a high volume truly portable structural concrete pump. In the preferred form, the various operating components are hydraulically operated by a hydraulic system provided with simple, manual controls. The pump is adapted for pumping through a three inch hose, for example, and distances of up to 1,000 feet, for example. Virtually any type of mix may be handled. In a preferred form of the invention, the pump may be built to have a pumping rate of, for example, 55 cubic yards per hour and may pump to a height as high as 150 feet.

A primary object of the invention is to make available a successful, high volume, truly portable structural concrete pump capable of the type of performance referred to in the foregoing. In realizing this purpose and objective, certain particular novel improvements and vfeatures are embodied in the pump. In a preferred form, the pump is of a duplex type embodying similar parallel pumping cylinders for the mix which are hydraulically actuated alternately. The operation is such as will be described in detail, that a smooth flow of mix or concrete, is realized from the common distributing pipe connected to the pair of cement pumping cylinders. Preferably the machine embodies cement mixing means on the trailer and a hopper for receiving the cement from the mixer. Improved valve means are provided for control of the ow of mix or concrete from the hopper to the pumping cylinders and for preventing back-flow in the delivery tubes back to the hopper. The cement control valves are hydraulically operated by hydraulic cylinders, control of which is integrated into the overall control of the system. One cement pumping cylinder operates at a time to pump through its delivery tube to the common discharge tube. When this cylinder operates, its communication with the hopper is cut off by a valve and a valve opens to allow its discharge to flow to the common discharge tube. At this time the other cement cylinder is retracting and a valve opens to allow communication between this cylinder and the hopper, whereas the discharge tube of this cylinder is closed by a valve to prevent backilow to the hopper. The invention provides improved valves for providing these functions. These valves are provided with rubber or flexible end or nose parts and provision is made for over-travel in their actuation so that the resilient end parts, when they meet resistance, are able to deform and thus fully and effectively accomplish their purpose of closing off the tube or channel even though the material being transferred is cement containing heavy aggregates. One of the objects of the invention is to achieve and realize improved and more effective and successful operation in a cement pump of this type by reason of the improved valves as described, and their manner of control and operation.

The discharge or downstream portions of the cement pumping cylinders are tapered, this part of the tubes being termed the swage. For successful operation of the pump, pumping the types of materials referred to, it is necessary that scouring action takes place keeping the swage portion free of build-up of concrete. In operation, cement, sand lines and water might collect on the inside surfaces of the tube or conduit, this accumulation being described as fatf In the swage at low velocity of movement the fat is squeezed into the aggregate and therefore the aggregate abrades the swage surface keeping it free of buildup. One of the objects of the invention is to provide for this particular construction and to thereby realize the results stated of keeping the swage surfaces free of build-up.

Further objects and additional advantages of the invention will become apparent from the following detailed description and annexed drawings wherein:

FIGURE l is a pictorial View of the preferred form of machine of the invention;

FIGURE 2 is a partly diagrammatic sectional View illustrating the layout of the pumping cylinders and control valves;

FIGURE 3 is a sectional view taken along the line 3 3 of FIGURE 2;

FIGURE 4 is a detail sectional View illustrating the construction of the pumping cylinders and the control valves;

FIGURE 5 is a diagram of the hydraulic control mechanisrns;

FIGURE 5A is a diagram of the auxiliary oil injection system;

FIGURE 6 is a diagram of the pilot control of the main relief valve 274.

FIGURE 7 is a diagrammatic view of sequencing valves V292 and 293.

Referring now more in detail to the pictorial View, FIGURE 1, the cement pump is mounted on a trailer having a chassis indicated generally at 10. The chassis has a forward frame part comprising members 11 and 13 which are joined, as shown. A bore is provided in these members for an upright 15 on the end of which is a dolly or caster wheel 16 for supporting the trailer in a level position when not being towed. 'I'he chassis includes longitudinal frame members such as the one as designated at 19 and a transverse frame member 2i). The trailer is provided with wheels, as shown at 22, and 23, appropriately mounted on an axle. Over the wheels are mud guards such as that shown at 25. Numeral 26 designates a step mounted on a bracket 27.

As previously indicated, the pumping cylinders and the control valves are hydraulically operated by hydraulic cylinders. The machine is provided with a tank for hydraulic fluid as designated at 36 supported on frame members as shown at 31 and 33. Numeral 35 designates an internal combustion engine in an apropriate housing provided for driving the hydraulic pump for the hydraulic uid which preferably is within the same housing. Numeral 36 designates a fuel tank for the internal combustion engine supported on frame members 37 and 38.

Numeral 40 designates the main hydraulic line connected to tank 30 by conduit 41. It is controlled by a valve operated by a hand Wheel 43.

Suitably supported on the chassis by frame structure including the members 33, is a concrete mixer 47 having a flared top as shown at 48. The mixer is provided with a flexible discharge conduit 50 provided with a bracket 51 at its end whereby it can be supported from a Hare at the upper end of the mixer 47. i

Numeral 53 designates the concrete hopper which is in a position to receive concrete from the mixer 47 and also to deliver concrete to the lpumping cylinders as will be described more in detail presently. Positioned adjacent to the hopper is the control panel 55 .provided with shield 56. Leading to the control panel are various hydraulic lines 58, 59 and 60. Appropriate pressure gaugesand any other suitable instruments are provided on the panel 55 as designated at 631 and 64 and also on this panel are the operating levers or handles for controlling the hydraulic system as designated at 65, 66, 67 and 68.

The main pumping or cement cylinders are positioned underneath the hopper and extend parallel to each other and lengthwise of the chassis 10. One of these cylinders may be s'een at 73 in FIGURE 1, the two cylinders being shown at 72 and 73 in FIGURE 2. The discharge conduits leading from the pumping cylinders are tapered, this part being termed the swage as designated at 75 and 76 in FIGURES 2 and 3. The swag'e is an important feature of the invention. The swage reduces the concrete cross-section beginning immediately at the point of termination of mechanical movement of the piston. The swage is required due to the loW velocity of the concrete where the cross-sectional area is large. Because of this low velocity, little if any, scouring takes place until the swage is reached. Scouring then begins and prevents the accumulation of fat (i.e.), sand, fines, etc. adjacent the walls of the swage.

Conduits are provided to deliver concrete from the hopper 53 into the pumping cylinders, this conduit being designated at 80 for the pumping cylinder 73 in FIGURE 3. Delivery of concrete through these conduits to the pumping cylinders is controlled by valves operated in cylinders, these valves being designated at 82 and 83 in FIGURE 1.

The pumping cylinders 72 and 73 discharge through the swages 75 and 76 into discharge conduits 86 `and 87, as shown in FIGURE 2, which join and together discharge into discharge swage 88 whichfmay have connected to it a flexible conduit for delivery of concrete to any desired point.

Additional valves are provided to prevent backow of concrete in the discharge conduits when the pumping cylinder of the other conduit is operating to discharge.

These valves are designated at 91 and 92 being angularly positioned with respect to the discharge conduits 86 and 87 as may be observed in FIGURE 1. .As previously mentioned, the cement cylinders and the valves are hydraulically actuated by hydraulic cylinders. The pistons of the cement cylinders are designated at 95 and 96 in FIGURE 2. These pistons will Abe described more in detail presently. The hydraulic actuating cylinders for the cement `cylinders are aligned with them and are designated at 100 and 101 in FIGURE 2. The pistons in these cylinders are designated at 102 and 103. Piston 102 is connected to piston 95 by a piston rod 106. Piston 103 is connected to piston 96 by a piston rod 107. The left ends of the hydraulic cylinders 100 and-101 are connected by a hydraulic line 110. Communication of hydraulic fluid to the end of cylinder 100 is by way of a line 111 and communication to the end of cylinder 101 is by way of a line 112. Details of the hydraulic system will be described presently.

Referring to the control valve 82 shown in FIGURE 3, it comprises a cylinder having in it a piston type valve member 115 which is operative to close off the conduit 80 to prevent backow of cement into the hopper 53. This valve will be described more in detail presently. It has a stem 116 connected to a piston 119 in a hydraulic cylinder 121. Communication of hydraulic fluid to the opposite ends Iof cylinder 121 is by way of conduits 123 and 124. The other valve 83 corresponding to the valve 82 is identical in construction and, therefore, need not be described in detail. These valves are positioned side by side, as may be observed in FIGURE l.

The valve 92 comprises a valve member 130 within the valve cylinder92. Its construction is like that of the Valves 82 and 83 which as stated will be described more in detail presently. The valve 130 is connected to a stem 131 which connects to a piston 132 in hydraulic cylinder 133 which is like the cylinder 121. Communication of hydraulic Huid to and from the opposite ends of cylinder 133 is by way of conduits 136 and 137. The Valve 91 is identical to the valve 92 and therefore, need not be described in detail. The operation 'of valves 91 and 92 is controlled in part by valves, the :detailed operation of which will be described presently.

As pointed out above, the control valves for controlling the cement flow are similar in construction. FIGURE 4 shows the details of valve 82. FIGURE 4 also shows the details of construction of one of the pistons. As shown in FIGURE 4, the cylinder of the control valve 82 is below the hopper 53 and is joined to the conduit part 80. The lower part of the hopper has a flange 150 joined to a similar flange 151 on the conduit 80. The hydraulic cylinder 121 has a flange 153 joined to a flange 154 on the cylinder 156 of the valve 82V. The stem 116 extends through a bore 158 in the end of hydraulic cylinder 121 and this bore may be sealed by an O-ring 160. The bore 161 in cylinder 121 is long enough to provide a certain degree of over-travel 162 of the piston 119. The purpose of this is to allow deformation of the rubber or flexible nose on the end of the Valve member 115 as Will be described in detail presently. The piston 119 may be of a standard construction having grooves and having sealing rings.

The valve member designated as a whole at 115 comprises a generally cylindrical piston part 167 having `a bore 168 and a larger threaded counter-bore 170 into which is threaded the stem 116. The end of member 167 is enlarged slightly as shown at 172. Both ends have angularly spaced axial notches to allow release of built-up lubricants and foreign matter. A threaded stem 174 extends through the bore 168 and it has a head 175 in the counterbore 170. This stem extends into a threaded bore 178 in a cylindrical member 179 having an end boss 180 of smaller diameter. Numeral 183 designates a group of felt wiper discs having central openings which t around the boss 180 `and the threaded stern 174 to have awiping action within the cylinder 156. Between these discs and the end face of member 179 is a exible sealing disc which may be made of rubber or the like 187 which is of larger -diameter than the bore of cylinder 156 and therefore, has a wiping and sealing `action within it. The cylindrical member 179 is of smaller diameter than the bore of cylinder 156 as shown. Fitting around member 179 is a flexible or rubber domed nose member 188. It has an end bore 189 to fit around cylindrical member 179 to which it is suitably secured. The lower part of the conduit where it joins the tapered conduit or swage 76 is slightly er1- larged as shown at 192 to accommodate deformation of the nose 188 when it is forced into the conduit part 80 for purposes of closing off oW of cement or aggregate or the like. From the foregoing those skilled in the art willv understand and appreciate the operation of the control valve. The valve member for closing off is forced into the conduit part 80 by the hydraulic cylinder and by reason of the over-travel of the piston as described the valve mem-ber is forced in so that the rubber nose part can deform, as illustrated by the broken line outline 194 to completely and effectively seal oi the passageway and prevent further passage of cement and/or aggregate. By this construction the operation is positive and effective despite the fact that the mix being transferred may contain aggregates of relatively large size, the construction being such as to adapt itself to such materials.

Lubricant may be admitted to the cylinder 156 through a ttin g 195.

Having reference to the pumping cylinder 72, it has a end ange 200 joined to an end ange 201 on the swage 76 and the conduit part 80 is fitted to the swage 76 at this point. The cement piston 96 is of composite construction as shown in FIGURE 4. It comprises a cylindrical body 205 of smaller diameter than the bore of cylinder 72 `and. having a bore 206, and an end part 207 of smaller diameter as shown. In the bore 206 is a cylindrical member 210 having a threaded bore 211 into which is threaded the end of the stem 107. Part 210 is threaded at the end and on this end is a nut 212 adjacent to the end of the body 205. There is also a nut 213 threaded onto the steam 107 adjacent to the end of part 210.

Radially extending projections are provided extending from the body 205 as designated at 217 and 218. These projections extend into bores 220 and 221 in the body 205 connecting with smaller axial bores 224 and 225. In these bores are pins 226 and 227 adjustable by screw members 230 and 231 received in axial threaded bores in member 205. These stems have bevelled inner surfaces as shown at 233 and 234 which engage with similar bevelled end surfaces on the ends of the projections 217 and 218. From the foregoing it will be observed that the projections 217 and 218 may be adjusted radially. The purpose of this construction is to provide adjustable guide means for the piston which is of limited area itself which reduces the amount of wear and adjustments can be thus made for wear thus contributing to the effectiveness and long life of the mechanism.

The driving end of piston 96 is of composite construction. Numeral 240 designates a disc welded to the end of cylindrical member 210. Secured to the face of this member is a rubber or composition end disc 241 which may be secured to disc 240 in any suitable manner. Numerals 243 and 244 designate metal ring members fitting around the end part 207 of ibody 205 which is of smaller diameter. Between the ring member 243 and disc 240 is a rubber seal ring 246 having a peripheral circumferential flange 248 which engages the interior surface of cylinder 72. Between the ring members 243 and 244 are two more sealing rings 250 and 251 which are similar to the ring 248 having similar peripheral circumferential flanges which engage the interior surface of cylinder 72. Preferably the sealing rings 243 and 244 have circular ribs thereon as shown which imbed in the sealing rings 246, 250 and 251. The sealing rings 250 and 251 are mounted back to back as shown.

The construction as just described has been found to be very effective :and efficient for purposes of pumping cement and the construction achieves this purpose in a positive manner, the construction being relatively maintenance free and characterized by having long operative life. The tapered portion of swage 76 has the purposes as described in the foregoing. It has an end flange 254 joined to an end flange 255 on the conduit 85.

The hydraulic system of the machine is arranged so that it will operate to pump cement entirely automatically. Referring briefy to the automatic sequence, the cement cylinders operate alternately. Whenever one of them is discharging cement its discharge is closed off from the hopper and its discharge conduit is open. At that time the discharge conduit of the other cement cylinder is connected to the hopper and its discharge conduit is closed off -by a valve to prevent backflow.

FIGURE 5 shows the hydraulic operating cylinders for the cement pumping cylinders. This figure shows the automatic hydraulic control system whereby the machine can be set to operate automatically to pump cement with the various components repeatedly going through the cycle referred to above.

Referring to FIGURE 5, the hydraulic system includes the tank 30 previously referred to and the valve 43. A filter 270 is provided, the pump being designated at 271. Numeral 274 designates a relief valve from which there is a return line 275 to the tank 30. Control of the cylinders 82, 83, 91 and 92 is by way of a four-way valve 280 which may be of a conventional type. Control of cylinders 72 and 73 is by way of a similar four-way valve 281. The automatic cycling is achieved further by Way of four-Way valves 283, 284 and 285 and the sequence valves 290,

6 291, 292 and'293. With reference to the hydraulic line, the heavy lines represent operating or driving hydraulic lines while the broken lines represent control lines which control the positioning of the valves. A check valve 300 is provided in the hydraulic line to the four-Way valve 280.

The approved J.I.C. (Joint Industrial Committee) symbols are used to represent the four-way valves 280 to 285. These are standard commercially available valves. Valves 283 and 284 are two position spring offset spool valves. Valves 280 and 285 are two position preferably detented spool valves. Valve 281 is a three position spring centered spool valve. The symbols illustrate how the pilot oil shifts the spool in each valve. The characters P and T indicate connections to pressure and back to the tank. The symbols indicate oil flow in the various spool positions resulting from application of controlling pilot oil pressure. Details of construction of the four-way valves may be found in currently available commercial catalogs.

The sequence valves 290, 291, 292 and 293 are pressure responsive valves, which, as will be explained, operate in response to a build-up of pressure and allow hydraulic control fluid to be delivered to the controlling four-way valves.

As pointed out, the hydraulic system can be set so that the machine operates or cycles automatically. However, it may be manually operated by way of the two three-way valves designated at 320 and 321.

Numeral 324 designates a working hydraulic fluid line to the four-way valves 280 and 281. The line 325 connected to four-way valve 280 has branches as shown connecting to the cylinders 82, 83, 91 and 92. In the position represented the control valve 82 for cylinder 83 is closed. As may be seen in FIGURE 3 when cylinder 72 is pumping valve 82 is closed and valve 91 is open or retracted. On the other hand, when cylinder 73 is pumping then valve 83 is closed and valve 92 is open. Thus, line 325 has a branch 326 connecting to one end of cylinders 83 and 91 and a branch 327 connecting to one end each of cylinders 92 and 82. Numeral 330 designates a fluid line connecting to another working port of four-way valve 280 having a branch connection 331 connected to one end each of cylinders 83 and 91 and a branch connection 332 connecting to one end each of cylinders 82 and 92.

Numeral 340 designates a working uid line connecting from four-way valve 281 to one end of cylinder 72. The corresponding end of cylinder 73 is connected by line 341 to another port of 4four-way valve 281. The opposite ends of cylinders 72 and 73 are connected by line 342.

The control line 250 connects from line 327 to sequence valve 291 and it is connected by a control line 351 to four-way valve 283. Control line 354 connects from line 332 to sequence valve and it connects by a control line 355 to four-way valve 284. A control line 356 connects from control line 340 to sequence valve 293 and a control line 357 and pilot 313 to four-way valve 285. A control line 359 connects from line 341 to sequence valve 292 and a control line 360 to the four-way valve 285.

Four-way valve 283 has a port connecting by line 365 to four-way valve 280 and it has a port connecting by line 366 to four-way valve 281.

Four-way valve 284 has a port connected by a line 369 to four-way Valve 280 and a port connected by a line 371 to four-way valve 281.

Three-way valve 321 is connected by a line 377 to relief valve 274 and a line 378 to four-way valve 285. Three-way valve 320 is connected to three-way valve 321 by line 380. It is connected by line 381 to line 369 and valve 302. It is connected by line 382 to four-way valve 280. Each of the four-way valves has a bottom connection as shown, leading back to the oil reservoir.

Sequence valves 290, 291, 292 and 293 are identical with one single exception. Sequence valves 290 and 291 7 are as supplied by the manufacturer while sequence valves 292 and 293 have a relief port drilled in the discharge system so that oil leakage around the spool cannot build pressure in line 360 or 357 until the actuating spool inthe sequence valves has fully shifted. This modification is described hereinafter.

Having reference to the line 342 connecting the cylinders 100 and 101 in FIGURE 5, an auxiliary system is provided in connection with this line which system is shown` in FIGURE A. As will be observed with respect to the cylinders 100 and 101, on the power stroke of one of these cylinders the other is acting as a slave. That is, the chambers on the back sides of the pistons in these cylinders are connected. The purpose of the auxiliary system as shown in FIGURE 5A is to inject pilot oil at system pressure, i.e., 1200 p.s.i., for example, into the slave system on each stroke. The injection system assures overfilling of the slave system so that the returning cylinderbottoms before the pumping cylinder, the need for being explained hereinafter.

Hav-ing `reference to the auxiliary system as shown in FIGURE 5A, a connection as shown, from the pilot oil line 378 connects to a needle valve 450l which in turn connects to a check valve 451. This check valve connects to a relief valve 452V which in turn connects to the line 342. The relief valve 452 has a connecting line 453 for release of oil back to the tank 30, as shown.

As will be observed, during the operating strokes of the pistons 102 and 103, the pressure drops or differentials across the pistons in the two cylinders are different, one of the pistons being on a working stroke and the other on .a return stroke. There is some migration or leakage of oil past the pistons and of course this migrationis greater in that cylinder where the differential across the slave connection, the system would not be operative due to the cumulation of the difference in oil migration. The injection system assures overlling of the slave system such that the returning cylinder bottoms before the pumping` cylinder; The relief valve 452 is set below sequence valve operating pressure, that is it may be set to operate at 900 p.s.i. whereas theA sequence valve may be set to operate at 1600 p.s.i. Accordingly, on each stroke a small volume of oil is injected to overll the slave system and on each stroke this excess is again forced out. Check valve 451 prevents reverse flow into the pilot system which would cause a false signal. The relief valve 452 may be of astandard commercial type allowing ow from line 378 through to line 342 and flow back out again to line 453 and to the tank 30.

FIGURE 6 shows the control of the relief valve 274. This main valve is pilot controlled in that it is normally open dumping all oil from the pump 271 to the tank 30. When the remote pilot control line is closed, stopping oil flow, the reliefvalve then functions, dumping oil to the tank only when the pressure exceeds the preset variable pressure. Further, if the remote pilot line is throttled, as opposed to being fully. closed, the relief valve pressure setting becomes a function of the throttled back pressure. This function is utilized to achieve preheating the hydraulic oil by forcing the hydraulic pump to do some work but since the concrete pump is not functioning at this time, no energy is removed from the oil and therefore, this energy goes into heat for heating the hydraulic oil which must be heated up to a certain temperature to function in the manner desired. In FIGURE 6, numeral 400 designates a pilot oil line and in this line is a valve 401 Which is shown diagrammatically, but which is preferably `a manually actuated throttling type of needle valve. Numeral 403 designates a two-way valve which is preferably a manually operated two-way valve. Line 404 extends from valve 403 back to the tank 30. From the foregoing it will be observed that control of the system is from the two-way valve 403 and the needley 8 valve 401. The relief valve 274 follows the valve 401 and heating of the hydraulic oil is achieved in a simple, but effective way. The relief valve 274 may be a cornmercially available type of relief valve, the setting of which is controlled 'by valves 401-and 403.

FIGURE 7 is a sectional view of one of the sequencing valves 292 or 293. These valves comprise a cylindrical body as designated at 410 having a central bore or cavity 412; an enlarged central cavity 414 and a cavity 416 at one end and inlet cavity 415.-Within the body of the valve is a spool 420 having enlarged portions as shown at 421, 422 and 423 which slide within the bore 412 and are sealed thereto by sealing rings as shown at 426, 427 and 42:8. The spool 420 has an extending threaded stem 431 extending through a bore 433' in the end of the body 292. The end of the stern 431 has an adjusting knob for adjusting a spring 438 which normally urges the spool in inward direction into the body 292. Spring 438 bears against piston 439 on stern 431. Piston 439 has an annular groove having init O-ring for sealing. The cavity 415 is an inlet chamber having a connecting conduit 359. The cavity 414 is an outlet chamber having connecting conduit 360. (See FIGURE 5.) Chamber 415 is connected to chamber or cavity 416 by way of an orifice 443. The cavity 414 is connected to the cavity 412 by way of a diagonal port 445. The operation of the sequencing valve is as follows. The hydraulic uid cornes into the conduit 359 into the cavity 415 and passes by way of the orice 443 into the cavity 416 so asto exert a pressure on the end face of the spool 420 tending to urgel it against the spring 438. The spool tends to move to the left as shown in FIGURE 7. The relationship between thespool and the bore in the body 292 is that of lands and grooves. As the enlarged portion 422 moves into the cavity 414 some of the hydraulic uid in cavity 415- leaks past the part 422 into thel chamber 414. It can then pass through the diagonal port 445 into-the cavity 412 and then is ported tothe tank through line 446 to prevent any build-upA of pressure in cavity 414 which is the control cavity connecting to the four-Way valve 285. (See FIGURES.) As the spool 4'20 continues to move tothe left, asy shown in FIGURE 7, the enlarged portion 421 or land moves to close thel end of diagonal port 445 and to prevent any further relief ofl buildup of pressure in cavity 414. The pressure in this cavity then suddenly increases to a pressure closely approaching the pressure setting of relief Valve 274. It approaches to within of this pressure. It will be observed, therefore, from FIGURE 5 that when the sequence valve 292 operates as described, the working pressure in cylinder 73 has reached this pressure, i.e., substantially 90% of the value of the setting of relief valve 274. This particular construction of the valve V292 makes this possible. Without this construction it would not be possible to realize the purpose of having the cylinders 73 yand 72 yoperate at working pressures closely approaching the setting ofthe relief Valve 274. This is described more in detail hereinafter. An exemplary Ipressure at which the valve 292 operates is 1600 pounds. At this pressure the four-way valves are triggered.

The purpose of port 445 may be realized in other ways. For example, the port may be in the spool 420 itself. The lands 421 and 422 may be a continuous land with the portr formed as an axial edge groove positioned to perform the same function.

The oil ow as described on FIGURE 5 has two main paths. First, the main oil :How which actuates the concrete valve cylinders 82, 83, 91 and '92. It also operates the main rams 72, and 73. The second oil flow system is the pilot oil flow as shown by line 377 from the relief valve. All' pilot oil, including the sequence valve oil flow are shown by dashed lines. `The main oil flow has previously been described. The pilot oil flow and its manner of control will next be described.

Pilot oil is taken from the relief valve and assumes the same pressure as the main oil system. It flows to a threeway valve 321 which has two main positions: an automatic position for automatic sequencing of the pump, and a manual position for manual sequencing of the concrete valves. Assuming the three-way valve 321 to be in the automatic position this pilot oil then ows through line 378 over to the main pilot valve 285, a four-way valve as described. Assuming this valve to be in the right-hand position, the pilot oil flows through the fourway valve and comes out the port C-l, in four-way valve 28S. The pilot oil flows then to valve 283, a spring offset or biased four-way valve. Due to the spring offset or bias, the pilot oil then flows automatically out to port C-1 through line 365 to the hydraulic cylinder which operates the four-way valve 280. This shifts the four-way valve 280 to the right allowing main oil iiow to ow out port C-1 and lines 326-327 thus setting up the concrete Valves 83 and 91 for discharge of the concrete from one working cylinder. This opens the right-hand discharge valve 91 (in FIGURE 2), and closes the righthand inlet valve 83. The valves 82 and 92 are positioned in their opposite positions by release of oil through lines 331 and 330, and port C-2 of valve 280. As these valve cylinders bottom, the pressure goes up to main relief valve setting of approximately 1600 p.s.i. In this case sequence valve 291 reads this pressure. This sequence valve has been preset to approximately 1500 p.s.i. At that pressure level, which is reached and exceeded when the valve hydraulic cylinders bottom, a signal is allowed to flow through the sequence valve over to the spring offset valve 283 through line 351. This deflects the spool in the Valve 283 against its offset spring allowing pilot oil to then ow from port C-2. Pilot oil then ows through line 366 to four-way valve 281. This pilot oil detlects the four-way valve to the right allowing main oil flow to ow out port C-1, line 340, into main ram cylinder 101. Concrete cylinder 72 then operates. When the ram 103, bottoms, pressure in line 340 builds up to main relief valve pressure. This pressure is, as with the concrete valve sequence valves, read by the main ram sequence valve, 293, `which has been preset to a pressure of approximately 1500 p.s.i. When this 1500 p.s.i. pressure is reached or exceeded the sequence valve 293 opens allowing pilot oil to flow through line 357 to the four-way valve 285. This shifts the spool in the four-way valve 285 to the left allowing main pilot oil to now flow from port C-2. A similar sequence to that described for the other working cylinder and valve cylinders now occurs. Hydraulic pilot oil ows through four-way valve 284 automatically coming out port C-1, to line 369. This oil flows to the fourway valve 280, shifting the four-way valve 280 to the left now allowing main oil to ow out port C-Z and lines 330, 331 and 332 which sets up the concrete valves for right-hand discharge. When the right-hand (or upper) concrete valve sequence has been established, pressure builds up in lines 330, 331 and 332, therefore increasing pressure in line 354 to sequence valve 290. This sequence valve, set for approximately 1500 p.s.i., opens when the pressure reaches or exceeds 1500 p.s.i. Oil is then allowed to ow through line 355.

When four-way valve 284 is deflected against the spring by oil pressure in line 355, pilot oil is able to flow through port C-2, to line 371. This oil ow shifts the main ram four-way valve, 281, to the left allowing main oil ilow to flow through port `C-2 to line 341. The right hand ram (in FIGURE 5) then travels forward causing concrete to be discharged from the right-hand side. When this ram 102 bottoms, pressure builds up to relief valve pressure. This pressure is read by sequence valve 292 through line 359. This sequence valve has been preset to approximately 1500 p.s.i. When pressure reaches or exceeds 1500 p.s.i., it opens and sequence oil is allowed to flow through line 360 to the main pilot valve 285. This shifts the pilot valve to the right allowing the main pilot oil to flow out port C-l which then re-establishes the sequence for left-hand discharge. The foregoing described the main pilot oil ow as -it affects the total hydraulic system during automatic operation.

Three-way valve 321 has a dual function. It provides for operation as an automatic system and also as a manual system. In manual operation pilot loil from line 377 is diverted to three-way valve 320 through line 380. When the valve 321 is in this position, no oil flow or pressure is generated in yline 378, the automatic pilot oil flow system. The sole function of the manual position is to allow the operator to cycle the concrete valves from left to right discharge or vice versa. It does this by taking pilot oil from line 377 through line 330' and three-way valve 320. Three-way valve 320 is actuated to a left or right position. -On left position oil flow is through line 382 to the pilot cylinder 301 of four-Way valve 280. This oil flow is suicient to shift four-way valve 280 allowing main oil flow in the main oil system to flow through four-way valve 280 out port C-1 and line 325 to set up the concrete valves for a simulated left-hand discharge. When three-way valve 320 is set for right position, the oil flow goes through line 381 to the right-hand pilot cylinder 302 of four-way valve 280. The same sequence of events occurs here. During manual operation no concrete can be pumped as there is no hydraulic pilot oil reaching the main pil-ot valve 285.

Thus it can be seen that the system has complete versatility providing for full automatic cycling or if desired, manual cycling of the system.

From the foregoing those skilled in the art will observe that the invention achieves and realizes all of the objects and advantages as stated in the foregoing as well as having many additional advantages that are apparent from the detailed description.

The foregoing disclosure is representative of a preferred form of the invention and is to be interpreted in an illustrative rather than a limiting sense, the invention to be accorded the full scope of the claims appended hereto.

What is claimed is:

1. In a concrete pump:

a cylinder;

a piston reciprocable in the cylinder toward and away from one end of the latter;

a conduit communicating with the cylinder at said end of the latter, said conduit having a concrete inlet, being tapered, progressively increasing in diameter as the cylinder is approached, preventing a swage, and having an outlet remote from the inlet and from the cylinder,

the reciprocation of the piston in one direction terminating within a plane transversely of the cylinder and conduit between said end and said conduit, and said taper beginning at said plane,

whereby inherent scouring action of concrete in the conduit begins immediately at said plane during movement of the concrete toward said outlet by `the piston moving in said one direction, thereby precluding undesired accumulation of concrete components at a zone in the conduit adjacent the cylinder.

2. The invention of claim 1, said conduit being frustoconical whereby the taper is uniform throughout the length -of the conduit.

3. The invention of claim 1, said inlet being disposed laterally of said movement of the concrete toward the -outlet and being -disposed in juxtaposition to said plane.

4. The invention 'of claim 2, said conduit and said cylinder having coaxial longitudinal axes.

5. In a concrete pump:

a cylinder;

a piston reciprocable in the cylinder;

a tubular inlet conduit communicating lwith the cylinder for conducting concrete thereinto;

a deformable valve member movable transversely across said conduit and into a Zone of engagement With the side wall of said conduit for closing the latter,

the conduit having a restricted section and an enlarged section presenting an offset being within the zone of engagement Iof said member with the side wall to enhance the seal effected between the member and the side Wall.

6. The invention of claim 5,

said member having an arcuate end nose,

said offset in the side Wall and said restricted section `of the conduit being disposed on the opposite side of the outermost extremity of said nose from said cylinder.

7. In a shut-off valving assembly:

a pair of interconnected cylinders having their axes substantially normal, d

one of the cylinders being provided with a side opening registering With the other cylinder;

a valve reciprocable in said other cylinder and provided with a dome-shaped resilient nose passing through the opening and into the one 4cylinder transversely of the one cylinder when the valve is moved to a position closing the one cylinder yagainst passage of materials through the latter,

said one cylinder having a first portion provided with an inside diameter substantially equal to the diameter of the nose and a second portion provided with an inside diameter greate-r'than said inside diameter lof the nose,

the nose being disposed to engage both of said portions When the valve is in said position whereby the nose deforms into full sealing relationship to the one cylinder.

8. The invention of claim 7, said second portionfhaving a dome-shaped section adjacent the first portion substantially complemental `with said nose and disposed on yone side -of said axis of the other cylinder.

References Cited UNITED STATES PATENTS 1,991,342 2/1935 Ball 103-170 2,998,7 81 9/ 1961l Triebel 103-49 3,042,149 7/1962 Comfort 92--86 X 3,068,806 12/1962 Sherrod 103-1-'69 3,198,123 8/ 1965 Wilkinson et a1. 10349 ROBERT M. WALKER, Primary Examiner. 

1. IN A CONCRETE PUMP: A CYLINDER; A PISTON RECIPROCABLE IN THE CYLINDER TOWARD AND AWAY FROM ONE END OF THE LATTER; A CONDUIT COMMUNICATING WITH THE CYLINDER AT SAID END OF THE LATTER, SAID CONDUIT HAVING A CONCRETE INLET, BEING TAPERED, PRORESSIVELY INCREASING IN DIAMETER AS THE CYLINDER IS APPROACHED, PREVENTING A SWAGE, AND HAVING AN OUTLET REMOTE FROM THE INLET AND FROM THE CYLINDER, THE RECIPROCATION OF THE PISTON IN ONE DIRECTION TERMINATING WITHIN A PLANE TRANSVERSELY OF THE CYLINDER AND CONDUIT BETWEEN SAID END AND SAID CONDUIT, AND SAID TAPER BEGINNING AT SAID PLANE, WHEREBY INHERENT SCOURING ACTION OF CONCRETE IN THE CONDUIT BEGINS IMMEDIATELY AT SAID PLANE DURING MOVEMENT OF THE CONCRETE TOWARD SAID OUTLET BY THE PISTON MOVING IN SAID ONE DIRECTION, THEREBY PRECLUDING UNDESIRED ACCUMULATION OF CONCRETE COMPONENTS AT A ZONE IN THE CONDUIT ADJACENT THE CYLINDER. 